Element LCD, power light on but no picture

[dezork]

Hi! I'm hoping someone can help me diagnose this.

I have an Element "eleft406". The red power light comes on when it's plugged in, and switches to blue, but there's no logo/video.

What's the most likely culprit? I've opened up the back panel, but I don't see any obviously blown caps.

[budm]

Re: Element LCD, power light on but no picture

For starter, we need GOOD CLEAR pictures of the whole backside of the TV so we can see all the boards first.

[dezork]

Re: Element LCD, power light on but no picture

Here's a gallery of all the boards and an overview shot of the panel.

Thank you!

[dezork]

Re: Element LCD, power light on but no picture

Bump

[CapLeaker]

Re: Element LCD, power light on but no picture

Can you explain better what the tv is and is not doing? Do the backlights come on? TUrn the TV on and check the voltage on the 400v capacitors on the PSU.

[dezork]

Re: Element LCD, power light on but no picture

The backlight doesn't come on. The only thing that visibly happens is that the power light switches to blue.

I'll grab a multimeter from work and test those caps tomorrow.

[dezork]

Re: Element LCD, power light on but no picture

Can you explain better what the tv is and is not doing? Do the backlights come on? TUrn the TV on and check the voltage on the 400v capacitors on the PSU.

The backlights don't come on. There is 2.7v across each of the 400v capacitors.

I can also hear a very quiet, but audible high frequency clicking noise coming from one of the boards (though I dont think it's from the PSU).

[dick_barton]

Re: Element LCD, power light on but no picture

Is that diode cracked or is it the light on it and is that a fuse in the second red box by the mains input terminals and if it is have you checked it for continuity?

[dezork]

Re: Element LCD, power light on but no picture

Is that diode cracked or is it the light on it and is that a fuse in the second red box by the mains input terminals and if it is have you checked it for continuity?

The diode isn't really cracked, it's just a reflection.

How do I test for fuse continuity? Sorry, bit of a newbie here.

[attainteddragon]

Re: Element LCD, power light on but no picture

continuity, or under .3 ohms.

[dick_barton]

Re: Element LCD, power light on but no picture

How do I test for fuse continuity? Sorry, bit of a newbie here.

With the set unplugged set your meter to ohms and place the leads either side of the fuse making good contact and it should read close to 0 ohms. OL is a blown fuse. You need to check first that it is a fuse because I can't really tell from your photo.

[CapLeaker]

Re: Element LCD, power light on but no picture

The backlights don't come on. There is 2.7v across each of the 400v capacitors.

I can also hear a very quiet, but audible high frequency clicking noise coming from one of the boards (though I dont think it's from the PSU).

That isn't right. Did you put both probes to the 400V cap and set the meter to read DC volts?

[dezork]

Re: Element LCD, power light on but no picture

That isn't right. Did you put both probes to the 400V cap and set the meter to read DC volts?

I tested it again, making sure to put the black probe on the side with the white stripe. I got a 3.0V reading on those caps with the power on.

[budm]

Re: Element LCD, power light on but no picture

It has to be measurement error, no way you can have 3.0VDC on the main filter caps and still get the LED power light to be on.
Please show us how you test the DCV on those 68uF 400vdc CAP (2 of them).

[dick_barton]

Re: Element LCD, power light on but no picture

With the set switched on can you carefully measure the voltage on each of the capacitors with the red lead on the + side of the capacitor and black on the other side and what do you read on each of them?

[budm]

Re: Element LCD, power light on but no picture

Another problem, if I remember correctly, other people in other thread that have similar boards as yours they found bad solder joints on the black connector between the power supply board and the main board.

[n8ves]

Re: Element LCD, power light on but no picture

OK, I'm having the exact same problem with my ELEFT406. The board layouts are exactly the same as another user posted here. Sniff test, nothing smells or looks burnt. The LCD works. There is a picture showing on it as I can tell by shining a flashlight on it. Have sound on it too. Just the backlight is the problem. I checked voltages on the power supply. There is about 75 volts DC on the four connectors that go inside the case. I assume these are for the backlight. Voltages on the other terminals check out OK. Is there another board inside the inner case? or are the back lights truly bad?